Standard Deviation tests and energy flow

Question 1

Is a result significant when..?

Answer 1

If the standard deviations do not overlap

Question 2

How reliable is this data?

Answer 2

If the standard deviation is small then it is more reliable

Question 3

What is a t-test

Answer 3

a measure of how large the difference is between 2 sets of results

Question 4

What is the critical value

Answer 4

95% / 0.05

Question 5

What happens when the data is very large

Answer 5

standard deviation becomes very large - so unreliable

Question 6

standard deviation

Answer 6

shows the variation from the mean

Question 8

Degrees of freedom (Df)

Answer 8

n1 + n2 - (how many tests but likely -2)

Question 9

are the results significantly different? (No)

Answer 9

• calculated T-value is less than the critical value
• This means there is no significant difference between the two means
• This means the variation in the data is simply due to chance
• reject the experimental hypothesis and reject the null hypothesis

Question 10

t-test are the results significantly different (yes)

Answer 10

• the calculated t-value is greater than the critical value
• this means there is a significant difference between the 2 means
• Variation is not just due to chance
• we would reject the null hypothesis and accept the experimental hypothesis